1. Field of the Invention
The present invention relates to an apparatus and method for inspection of the surface of an object to be inspected.
2. Description of the Related Art
Conventionally, as described in JP-A-63-143830, since various defects are present on a silicon wafer plate (that is a semiconductor material) and cause a reduction in the quality of an integrated circuit manufactured, the silicon wafer plate is inspected by a plate defect inspection apparatus.
Recently, since the density of an integrated circuit has been increased, and rigorous inspection has been carried out on defects, it is necessary that the types of defects be discriminated and detected.
Many types of defects may be present on a wafer plate. One type of the defects is a haze such as a stain attached to the surface of the plate, hazy tarnish, or a surface irregularity. It is requested to detect those defects.
The haze is distributed in a relatively large area and has an extremely thin film shape. A conventional defect detection method is to detect light that is generated from a fine particle (such as dust) or a microscopic scratch and scattered in an extremely small area. It is difficult that this method is used to detect a haze. Therefore, an effective method for detecting such a haze is required.